The invention relates to a device for dispensing a fluid according to the preamble of claim 1. Such device is known from FR-A-2 331 485.
U.S. Pat. No. 5,368,207 discloses a device comprising a pressure container in which a fluid to be dispensed can be stored in a first chamber, while a second chamber is included for storing and dispensing a propellant. Via pressure control means, the second chamber is in fluid communication with the first chamber. The pressure control means are arranged for passing the propellant from the second chamber into the first chamber at a specific, preset pressure. In such device, during use, the fluid is pressurized in the first chamber by means of the propellant and when suitable dispensing means are opened, the fluid is thus driven from the first chamber.
This known device has as a drawback that the ratio between the volume of the first chamber and the volume of the second chamber is unfavorable. To enable storing sufficient propellant in the second chamber for dispensing the complete contents of the first chamber at a suitable pressure, the second chamber must be relatively large in relation to the first chamber. As a consequence, the device as a whole has an unfavorable ration between outside dimensions and effective content of the first chamber.
It has already been proposed to increase the pressure in the second chamber such that at a smaller volume, the same amount of propellant can be included therein. However, this has the drawback that the pressure control means and the walls of at least the second chamber should be accommodated to such increased pressures, which is technically complicated and costly. Moreover, such increased pressures are usually unacceptable without extreme safety measures, on account of conditions with respect to production and usage.
Further, such device has the drawback that relatively much material is used and that such device is relatively heavy.
FR-A-2 331 485 discloses a device for dispensing a fluid, comprising a container having a first and second compartment. In the first compartment a fluid to be dispensed can be introduced, in the second compartment the propellant. An opening is provided between the first and second compartment in which pressure control means are arranged for controlling the pressure of propellant flowing from the second into the first compartment. In this device fillers are provided in the second compartment for adsorbing and absorbing part of the propellant, in order to enable storage of a relatively large quantity of propellant under relatively low pressure. This known device is arranged for spraying furniture polish and the like. During use the pressure of the propellant is arbitrarily chosen.
The object of the invention is to provide a device according to the introduction, wherein the drawbacks mentioned are avoided, while the advantages thereof are retained. To that end, a device according to the invention characterized by the features of claim 1.
In a device according to the present invention, a filler is included in the second compartment for associating at least a portion of the propellant, which portion can hence be introduced into the second compartment without the pressure therein being considerably increased. The surprising effect thus achieved is that under equal conditions of use, a considerably larger volume of propellant can at a preselected pressure be introduced into the second compartment filled with propellant, than in a second chamber of the known device, at the same pressure. This means that in a device according to the invention, the second chamber can be relatively small compared with the first chamber, while a large volume of propellant can nevertheless be introduced into the second chamber at a relatively low pressure. This means that no specific measures are necessary for rendering the pressure control means and the walls of the second compartment resistant to extreme pressures.
Surprisingly, it has been found that for dispensing carbonated beverages, in particular beer, already a relatively slight excess pressure in the chamber in which beverage to be dispensed is included, relative to the environment, leads to a particularly favorable dispensing pattern. In particular, a number of glasses of beer having a suitable head of foam and an optimum CO2 content can be drawn therewith in a relatively fast manner.
In a device according to the invention, techniques known form the aerosol industry, such as valve parts and container, can be utilized in an advantageous and surprising manner.
In an advantageous embodiment, a device according to the invention is characterized by the features of claims 4.
The advantage achieved by using relatively pure carbon dioxide as propellant, with the fillers being substantially formed by activated carbon fibers, is that a particularly large volume of propellant can be introduced into a particularly small space at a suitable pressure, due to the large specific internal and external surface area of the activated carbon fibers. In particular when a device according to the invention is used for dispensing carbonated beverages, the advantage achieved by the relatively high purity is that the propellant can be brought directly into or above the beverage to be dispensed, so that the device may be of a simple construction. Moreover, a desired equilibrium situation is thus always maintained in the head space of the first compartment, which has a positive effect on the quality of the beverage to be dispensed and prolongs the shelf life thereof.
For the use of a device according to the present invention for storing and dispensing beer, in particular of the lager type, an excess pressure is preferably maintained in the head space of the storage compartment (first compartment) of between 0.65 bar and 1.0 bar (1.65-2.0 bar absolute) so as to obtain and maintain an equilibrium in the CO2 content of about 4.6 g CO2 per liter beer at a beer temperature of between 5xc2x0 C. and 10xc2x0 C. From Table 1, for other carbonated beverages, the desired excess pressures for desired carbon dioxide contents can be read.
For associating CO2, activated carbon is preferably used, such as activated carbon of the type GF40 or R1Extra, both supplied by the firm Norit, Amersfoort, the Netherlands, as will be further indicated in the specification.
Per liter of fluid to be dispensed, in particular carbonated beverage, preferably between 2 and 20 g activated carbon is included in the second compartment. More in particular, between 6 and 18 g activated carbon is included. Thus, at acceptable pressure, a sufficient amount of CO2 or a like propellant can be associated, while practically no excess carbon is present.
Per liter of fluid to be dispensed, in particular carbonated beverage, preferably between 1 and 10 g of CO2 is stored as pressure medium in the second compartment. It has been found that such amounts are sufficient for displacing the beverage at least substantially completely. In, particular an amount of between 2 and 8 g CO2 proves to yield very good results.
Through a suitable dimensioning of the flow-out device, beer can already be drawn in a suitable manner, i.e. at a proper tapping rate and with a right CO2 content and a nice, full head of foam, at the equilibrium excess pressure of carbon dioxide.
Preferably, there are provided excess pressure relief means for the first and/or second compartment for letting off at least a portion of the pressure medium in a controlled manner when unduly high pressures occur. To that end, for instance, a valve may be arranged or local weakenings may be consciously provided, for instance at folded seams, attachments or the like.
Including both the first and the second compartment in the container offers the advantage that a user need not perform any assembling operations before the device can be used. This adds to the ease of use, comfort and safety of the user. Moreover, assembling errors are thereby avoided, so that waste is prevented. By providing means for filling the second compartment with propellant, from the outside of the container, the advantage achieved is that this filling operation can be performed up to any suitable moment, for instance after filling and after treatment of the fluid in the first compartment. This is advantageous in particular when such fluid in the container is to be exposed to substantial changes of temperature, such as, for instance, in a pasteurization pass.
In an alternative embodiment, a device according to the invention is characterized by the features of claim 8.
In such embodiment, prior to use, the second compartment which is accommodated in a preferably cartridge-shaped housing, can be coupled to the container and be brought into fluid communication with the first compartment. It is thus ensured that prior to use, the container is practically pressureless, or at least retains a relatively low pressure. Only after coupling to the second compartment can the desired increase of pressure be effected. Moreover, the first compartment and the second compartment can be treated separately, which is advantageous in terms of production and use. Indeed, the container with the first compartment can, for instance, be exposed to changes of temperature without the propellant in the second compartment being influenced thereby, while, moreover, the different parts can be manufactured, stored, transported, possibly reused or discharged separately. Further, the advantage thus achieved is that, if so desired, several containers can be brought and kept under pressure simultaneously or consecutively with the same second compartment.
In a further, particularly advantageous embodiment, a device according to the invention is further characterized by the features of claim 9.
The use of a dip tube mounted on the first compartment offers the advantage that this assembly can be placed as a unit. This is advantageous in particular when the dispensing means are integrated into this assembly as well. The dip tube provides that the first compartment can be emptied completely, in a suitable manner. Installation of the assembly can preferably take place after the filling of the first compartment. In fact, it is observed that such assembly can also be supplied separately from the first compartment, such that it can be placed by a user directly prior to use. Moreover, such an assembly can be designed for refilling, at least for being used several times.
The invention further relates to a method for keeping under pressure and dispensing a fluid, characterized by the features of claim 11.
With such a method, the advantage achieved is that by means of a relatively simple device, a relatively large amount of fluid can be dispensed without requiring extreme compression of the propellant and without requiring accommodating propellant in a chamber having a relatively large volume compared with the quantity of fluid to be dispensed. Hence, a device to be used with such a method may be of a relatively small, simple and light design, without this having an adverse effect on the ease of use and safety of the user.
The invention further relates to a pressure cartridge for use in a device, assembly or method according to the invention, characterized by the features of claim 12.
Such a pressure cartridge may, for instance, be designed as a relatively small container, suitable for bringing and maintaining a first compartment under pressure, but may also be designed as, for instance, a CO2 cylinder for bringing and maintaining a number of first compartments or a barrel of a relatively large content under pressure. Of course, a pressure cartridge according to the invention may be filled with all types of fillers, depending on the propellant that is to be stored therein, yet as filler, activated carbon fibers are preferred, in combination with CO2, in view of the relatively universal applicability and possibilities of reuse thereof and the purity of the CO2, as a result of which it can be introduced directly into or above the beverage.
In further elaboration, a pressure cartridge according to the invention is characterized by the features of claim 13.
The use of pressure control means for maintaining, during use, a relatively constant excess pressure, offers the advantage that fluid can always be dispensed in a substantially equal manner. In this respect, accommodating the pressure control means in the pressure cartridge offers the advantage that they can be reused and activated in a relatively simple manner, while they can moreover be used as closing means for the pressure cartridge, if so desired.
The invention moreover relates to the use of a pressure cartridge according to the invention for dispensing a carbonated beverage, in particular beer.
Further advantageous embodiments of a device or method according to the invention are given in the subclaims.